EXCHANGE 


8061  '12  NVP  'It 
'A  ' 


POTASH  IN  ILLINOIS  SHALES 


BY 


MINER  MANLY  AUSTIN 

A.  B.  Lawrence  College,  1916 
M.  A.  University  of  Illinois,  1918 


THESIS 

Submitted  in  Partial  Fulfillment  of  the  Requirements  for  the 

Degree  of 

DOCTOR  OF  PHILOSOPHY 
IN  CHEMISTRY 

IN 

THE  GRADUATE  SCHOOL 

OF  THE 

UNIVERSITY  OF  ILLINOIS 
1920 


REPRINTED  FROM  THE  JOURNAL  OF  INDUSTRIAL  AND  ENGINEERING  CHEMISTRY 
Vol.  13,  No.  12,  page  1144.    December,  1921 


POTASH  IN  ILLINOIS  SHALES 


BY 


MINER  MANLY  AUSTIN 

A.  B.  Lawrence  College,  1916 
M.  A.  University  of  Illinois,  1918 


THESIS 

Submitted  in  Partial  Fulfillment  of  the  Requirements  for  the 

Degree  of 

DOCTOR  OF  PHILOSOPHY 
IN  CHEMISTRY 

IN 
.    THE  GRADUATE  SCHOOL 

OF  THE 

UNIVERSITY  OF  ILLINOIS 
1920 


REPRINTED  FROM  THE  JOURNAL  OF  INDUSTRIAL  AND  ENGINEERING  CHEMISTRY 
Vol.  13,  No.  12,  page  1144.     December,  1921 


*    •  •  „«  *••  .•< 

V.  ::••': 


ACKNOWLEDGMENT 

This  investigation  was  carried  on  in  the  Chemical  Lab- 
oratory of  the  University  of  Illinois  during  the  years  1918- 
1920.  It  was  undertaken  at  the  suggestion  of  Professor  S.  W. 
Parr  and  carried  out  under  his  direction. 

The  writer  takes  this  opportunity  to  express  his  most  sin- 
cere thanks  and  appreication  to  Professor  Parr  for  the  valu- 
able help  and  direction  which  he  has  given. 

The  writer  also  wishes  to  thank  Dr.  F.  W.  De  Wolf,  Pro- 
fessor T.  E.  Savage,  and  Professor  Robert  Stewart  for  the 
assistance  which  he  has  received  from  them. 


[Reprinted    from    the   Journal    of    Industrial    and    Engineering    Chemistry, 
Vol.  13,  No.   12,  page  1144.      December,  1921.] 


Potash  Shales  of  Illinois1 

By  M.  M.  Austin  with  S.  W.  Parr 

DEPARTMENT  OF  CHEMISTRY,  UNIVERSITY  OP  ILLINOIS, 
URBANA,  ILLINOIS 

Investigation  of  the  potash  shales  of  Illinois  was  taken 
up  in  1917  in  an  effort  to  find  values  in  the  residues  from  cer- 
tain shales  which  were  under  investigation  in  the  laboratory 
of  applied  chemistry  at  the  University  of  Illinois,  with  primary 
reference  to  the  amount  of  oil  to  be  obtained  on  destructive 
distillation.  The  shale  from  one  region,  Johnson  County, 
yielded  from  45  to  50  gal.  of  oil  per  ton  and  would  therefore 
be  of  interest  for  its  oil  yield  alone.  Other  shales  which  were 
of  questionable  value  from  the  standpoint  of  oil  yield  might 
come  into  the  field  of  possible  technical  utilization  if  other 
values  could  be  discovered  in  them.  This  constituted  a  pri- 
mary reason  for  examining  all  samples  for  other  values,  such  as 
phosphorus  and  potash.  The  samples,  eighteen  in  all,  were 
furnished  through  the  courtesy  of  the  Illinois  State  Geo- 
logical Survey.  They  came  from  localities  widely  distributed 
over  the  state.  None  of  the  samples  contained  phosphorus 
in  more  than  a  trace.  Although  the  majority  contained  2  or 
3  per  cent  of  potash  (KsO),  which  is  normal  for  shale  rock, 
two  formations  showed  a  potash  content  of  from  5  to  5.8  per 
cent  (K20).  Of  these  latter  two,  the  more  important  is  a 
black  carbonaceous  shale  which  outcrops  at  frequent  inter- 
vals over  a  distance  of  about  7  mi.  in  Union  County.  The 
other  is  a  green  sandy  shale  of  entirely  different  character 
occurring  in  Lee  County  near  Dixon,  111. 

POTASH  SHALES  IN  CEMENT  MANUFACTURE 

From  a  study  of  the  potash  situation  it  would  seem  that 
one  of  the  hopeful  sources  for  a  domestic  supply  resides  in 
the  recovery  of  potash  as  a  by-product  from  the  manufacture 
of  cement.  Even  though  the  average  shale  used  in  the  cement 
mix  does  not  contain  more  than  1.5  to  2.5  per  cent  of  potash 
(K20),  the  potential  supply  from  this  source  would  be  very 
great,  as  a  result  of  the  tremendous  tonnage  of  cement  being 
produced. 

The  Illinois  shales  that  we  are  here  considering,  instead 
of  having  an  average  potash  content  of  2  or  even  25  per  cent, 
have  a  content  of  5  per  cent.  They  compare,  therefore, 
very  favorably  with  the  greensands  of  New  Jersey.2  The 
first  question  that  naturally  arises,  therefore,  relates  to  the 
suitability  of  these  Illinois  shales  for  the  purpose  of  compound- 
ing a  suitable  cement  mix 

1  Presented  before  the  Division  of  Fertilizer  Chemistry  at  the  60th 
Meeting  of  the  American  Chemical  Society,  Chicago,  111.,  September  6  to 
10,  1920. 

»  Chem.  Met.  Eng.,  22    (1920),  815. 

(1) 

478665 


Illinois  shales  of  suitable  composition  for  cement  making, 
according  to  Bleininger,1  are  shown  in  Table  I.  For  com- 
parison, two  of  the  high  potash  shales  are  shown  in  parallel 
column*. 

TABLE  I— COMPARISON   OP  ILLINOIS  SHALES   WITH  REFERENCE  TO  THBIB 
CBMBNT-MAKING  PROPERTIES 

Average  of  8 

Illinois  Shales  *•— Illinois  Potash  Shales-^ 

CONSTITUENT                 (Bleininger)  Sample  1  Sample  2 

SiOt                                   61.56  53.8  55.0 

AhOi                                  16.12  17.7  16.3 

FejO»                                  2.96  5.8*  6.0» 
FeO                                      3.52 

CaO                                     0.94  0.7  0.3 

MgO                                   1.79  1.8  1.5 

KiO                                      2.90  5.0  4.9 

Na2O                                    0.82  0.5  0.4 

Ignition  loss                              6.72  11.9  13.0 

»  Total  iron  calculated  to  FejO». 

Samples  1  and  2  are  the  black  carbonaceous  shale  from 
Union  County.  It  will  be  observed  that,  except  in  potash 
content,  they  vary  but  little  in  composition  from  the  average 
of  other  shales  which  are  said  to  be  suitable  for  cement  mak- 
ing. Their  high  potash  content  might  be  an  advantage  also 
in  the  formation  of  the  clinker,  since  it  would  tend  to  lower 
the  burning  temperature. 

Other  factors  which  are  important  in  evaluating  these 
shales  for  cement-making  purposes  are  as  follows: 

Sample  1  Sample  2 

Silica-alumina  ratio  3 . 02  3 . 37 

Inert  mineral  content  0.63  0.75 

Sulfur  2.40  2.80 

The  silica-alumina  ratio  is  in  the  most  advantageous  zone, 
and  -he  inert  mineral  content  is  low.  The  sulfur  occurs 
principally  in  microscopic  form  as  pyrite. 

In  average  American  practice  the  raw  mix  will  contain 
0.7  to  1.0  per  cent  of  K20.  On  the  basis  of  f>5  per  cent  re- 
covery, which  according  to  Huber  and  Reath2  it  seems  roason- 
able  to  expect,  there  would  result  an  average  yield  of  2.9  Ibs. 
of  potash  per  barrel  of  cement.  On  the  same  basis,  the  potash 
shales  whose  analyses  are  given  in  Table  I  should  yield  5.4 
Ibs.  per  bbl. 

One  other  region  in  the  state  has  thus  far  supplied  a  shale 
with  a  high  potash  content,  but  its  cement-making  possibil- 
ities have  not  been  determined.  This  shale,  from  Dixon, 
in  Lee  County,  contains  5.8  per  cent  of  potash.  It  is  coarse- 
grained and  friable.  While  its  green  color  is  suggestive  of 
the  greensands  of  the  East,  the  geological  character  of  the 
material  is  quite  different,  as  will  be  shown  later. 

CONSTITUTION  OF  ILLINOIS  POTASH  SHALES 

The  shales  from  Union  County  are  peculiar  in  that  they 
contain  a  small  percentage  of  oil,  present  in  the  free  state. 
Thus  has  no  industrial  significance,  but  it  adds  to  the  other 
volatile  constituents,  such  as  water  of  hydration,  so  that 

»  Illinois  State  Geological  Survey.  Bulletin  17  (1912). 
2  Chem.  Met.  Eng.,  16  (1917),  702. 

(2) 


the  reduction  in  weight  upon  ignition,  as  shown  in  Table  I, 
amounts  to  about  12.5  per  cent  of  the  raw  material,  and  the 
potash  content  of  the  residue  becomes  5.75  per  cent  With 
the  Dixon  shale  but  little  loss  occurs  on  ignition,  and  the 
potash  percentage  is  about  the  same  in  either  the  ignited  or 
the  raw  state. 

ACTION  OF  SULFTTRTC  ACID — No  very  simple  or  direct  method 
was  available  for  determining  the  form  of  combination  in  which 
the  potash  was  held.  One  procedure  consisted  in  digesting 
1  g.  of  the  sample  with  25  cc.  of  concentrated  sulfuric  acid, 
heating  until  about  half  of  the  acid  had  been  removed,  dilut- 
ing, filtering,  washing,  and  igniting  the  residue,  and  analyzing 
it  for  total  potash.  The  percentage  of  potash  found  was 
considered  as  being  in  some  other  than  the  feldspathic  form. 

By  this  procedure  62  per  cent  of  the  total  potash  was  found 
to  be  removed  from  the  Union  County  shales,  while  from  the 
Dixon  shale  only  about  15  per  cent  was  removed,  showing 
a  marked  difference  in  the  chemical  composition  of  the  two 
shales.  Further  proof  of  this  difference  was  desired.  It 
is  true  that  in  the  process  of  cement  manufacture  the  potash 
would  be  equally  recoverable  in  either  case;  but  from  any 
other  standpoint  differences  in  the  ease  with  which  the  potash 
might  be  removed  by  chemical  solvents,  or  concentrated 
into  a  form  for  more  ready  extraction,  might  make  a  wide 
difference  in  the  value  of  the  shales  from  the  two  sources. 

It  is  not  the  purpose  of  this  discussion  to  go  into  the  details 
of  the  experiments  to  determine  the  chemical  character  of 
the  potash-bearing  constituents.  The  method  of  analysis 
suggests  that  the  potash  in  the  Dixon  shnle  is  chiefly  or  al- 
together feldspathic  in  combination,  and  that  the  major  part, 
at  least,  of  the  potash  in  the  Union  County  shale  is  in  some 
combination  more  nearly  resembling  the  glauconitic  or  green- 
sand  formations.  These  formations  are  considered  as  being 
potassium-iron  silicates  with  an  average  potash  content  vary- 
ing from  5  to  7  per  cent  K20. 

MICROSCOPIC  EXAMINATION — Thin  sections  for  study  under 
the  microscope  were  prepared.  No  very  positive  information 
came  from  such  studies.  In  general  it  seemed  evident  that 
the  Union  County  shales  had  passed  through  extensive  second- 
ary decompositions  and  that  the  Dixon  shales  had  not. 
Both  types,  however,  even  in  the  undisturbed  condition  of 
the  deposits,  had  their  ultimate  particles  in  such  a  finely 
divided  state  as  to  render  impossible  their  re-solution  and 
study  under  the  microscope. 

TESTS  WITH  PLANTS — A  third  method  of  study  into  the 
probable  type  of  composition  was  as  follows:  Accepting  the 
generally  conceded  fact  that  potash  in  feldspathic  combination 
ie  only  slightly,  if  at  all,  available  directly  as  plani  food, 
further  data  on  composition  might  be  obtained  from  experi- 
ments to  determine  whether  some  of  the  potash  in  the  Union 
County  shales  was  directly  available  for  plant  use.  Some 
foundation  for  this  theory  was  already  afforded  by  the  fact 

(3) 


that  62  per  cent  of  the  total  potash  was  soluble  in  acid.  If 
the  Union  County  shales  were  treated  with  strong  acid  in 
such  a  manner  as  to  remove  all  their  acid-soluble  potash,  and 
if  the  residue  with  the  remaining  38  per  cent  of  potash  (pre- 
sumably in  feldspathic  combination)  were  submitted  to  plant 
action  and  found  lacking  in  available  potash,  this  would  afford 
a  still  further  proof  in  the  chain  of  evidence  as  to  the  type  of 
potash  combination  in  the  original  shale. 

It  is  not  our  purpose  to  go  into  the  details  of  the  results 
from  these  pot  cultures,  which  were  conducted  by  the  Agron- 
omy Department  of  the  College  of  Agriculture,  further  than 
to  correlate  the  results,  so  far  as  they  have  a  bearing  upon 
the  composition  of  the  shales. 

In  Table  fl  there  is  shown  the  behavior  of  the  various 
shale  materials  when  applied  to  a  peat  soil  deficient  in  potash. 
Buckwheat  was  selected  as  the  plant  most  responsive  to  the 
varying  treatments.  An  equivalent  quantity  of  potash  was 
added  in  each  case,  except  to  the  check  pots  which,  of  course, 
contained  no  added  potash  in  any  form.  Each  pot  was 
made  up  of  7  kg.  of  peat  soil,  60  g.  of  pulverized  limestone, 
and  the  various  types  of  shale  material,  ground  to  pass  a 
100-mesh  sieve,  and  in  an  amount  that  would  carry  into  the 
soil  mixture  in  each  case  a  total  potash  content  of  1.61  g. 
(K20). 

TABLE  II— COMPARATIVE  STUDY  OP  BUCKWHEAT  GROWTH,  USING  SHALE 
MATERIALS  op  DIFFERENT  COMPOSITION 

CONDITION  OP  PLANTS  Six  WEEKS 
No.          DESCRIPTION  OP  POTS  APTER  PLANTING 

1  Check  pot  using  peat  soil   with 

insufficient  potash  Poor  growth 

2  Peat  soil  as  in    1,    with  Dizon         Poor  growth,  not  distinguishable 

shale  from  No.  1 

3  Peat    soil  as   in    1,    with   Union 

County  shale,  less  62  per  cent          Poor  growth,  not  different  from 
of  potash  by  acid  extraction  Nos.  1  and  2 

4  Peat  soil   as   in  1,    with  Union         Excellent  growth  more  dense  and 

County  shale  ignited  taller  than  Nos.  1, 2,  or  3 

5  Peat  soil  as  in  No.  1 ,  with  Union         Excellent  growth,  not  distinguish- 

County  shale,  Sample  1  not  able    in  density  or  vigor  from 

ignited  No.  4 

6  Peat  soil  as  in    1,  with  Union          Excellent    growth,  equal  in  every 

County  shale,  Sample  2  not  respect  to  Nos.  4  and  5 

ignited 

This  amount  of  potash  represents  the  weight  per  acre  that 
would  be  present  in  a  normal  soil  which  was  deemed  to  have 
an  adequate  supply  of  that  constituent.  The  results  pre- 
sented in  the  table  are  also  clearly  shown  in  the  photographic 
reproduction. 

Pot  1  is  the  check,  with  deficient  potash.  Pot  2  has  the 
standard  equivalent  of  1.61  g.  of  K20  added  in  the  form  pres- 
ent in  the  Dixon  shale,  and  Pot  3  has  the  same  addition  in 
the  form  of  acid-insoluble  residue  from  the  Union  County 
shale.  An  examination  of  these  three  pots  seems  to  warrant 
the  conclusion  that  potash  in  any  available  form  is  lacking 
in  each  case.  This,  therefore,  would  seem  to  confirm  the 
previous  assumption  that  the  potash  present  in  Pots  2  and 
3  is  in  the  feldspathic  form. 

By  further  reference  to  Pots  4,  5,  and  6,  there  is  an  equally 
(4) 


BUCKWHEAT  PLANTS  GROWING  ON  PEAT  Son.  TO  WHICH  VARIOUS  SHALB 

MATERIALS  HAVE  BEEN  ADDED 

1— Check  4-^-Union  Co.,  ignited 

2 — Dixon  shale  5 — Union  Co.,  No.  1 ,  not  ignited 

3 — Union  Co.,  acid-extracted     6 — Union  Co.,  No.  2,  not  ignited 

obvious  indication  that  in  these  pots  potash  is  present  in  a 
form  available  for  plant  use;  and  since  the  only  variable  in 
the  experiment  is  the  acid-soluble  constituent,  it  is  evident 
that  the  potash  utilized  by  the  plant  comes  from  this  source. 
Moreover,  ignition  or  non-ignition  of  the  shale  does  not 
affect  the  property  of  the  potash  so  far  as  food  availability 
is  concerned.  It  would  be  of  scientific  interest,  of  course, 
to  be  able  to  say  more  definitely  in  what  form  was  the  potash 
combination  here  found.  We  have  compared  it  thus  far 
in  the  discussion  to  the  greensands  of  the  eastern  United  States 
which  are  true  glauconites.  The  most  that  can  be  said  of 
these  shales  is  that  they  are  glauconitic  in  type.  They  may 
have  been  originally  a  feldspathic  deposition  which  has  under- 
gone secondary  decomposition  in  situ.  .Indeed,  the  region 
has  other  striking  examples  of  decomposition,  for  example, 
the  very  pure  deposits  of  amorphous  silica,  found  so  abun- 
dantly in  Union  County,  as  well  as  some  very  pure  kaolins. 
So  far  as  conformity  to  greensand  or  glauconitic  conditions 
is  concerned,  there  is  every  justification  for  such  a  classifi- 
cation, as  may  be  seen  from  the  following  quotation,1  indicating 
the  geological  conditions  under  which  the  true  glauconites 
are  supposed  to  have  been  formed: 

The  organic  matter  transforms  the  iron  into  sulfide  which  may 
be  oxidized  to  hydrate,  sulfur  being  at  the  same  time  liberated. 
This  sulfur  would  oxidize  to  sulfuric  acid,  which  would  decom- 
pose clay,  setting  free  colloidal  silica,  aluminium  being  removed 
in  solution.  Thus,  we  have  colloidal  silica  and  hydrated  iron 
in  a  state  most  suitable  for  their  combination.  The  potash 
which  is  necessary  to  complete  the  composition  of  glauconite 
may  be  derived  from  the  decomposed  fragments  of  crystalline 
rocks  like  orthoclase  or  white,  mica. 

Upon  analysis  of  the  shale  for  iron  in  the  pyritic  form  by 
methods  developed  in  this  laboratory,2  it  appears  that 
when  the  pjTitic  iron  is  deducted  from  the  total  iron  of  the  shale 

1  W.  B.  Claike,  J.  Geol.,  13  (1900),  509. 

»  A.  |R.  Powell,   with  S.  W.  Parr,   University  >f  Illinois  Engineering 
Experiment  Station,  Bulletin  111  (1919). 

(6) 


there  remains  3.8  per  cent  of  iron  available  for  combination 
with  the  3.1  per  cent  of  potash  present  in  the  acid-soluble  form, 
an  amount  which  approaches  the  ratio  for  glauconitic  material 
with  sufficient  approximation  to  warrant  the  classification 
thus  proposed,  viz.,  not  true  glauconite  but  glauconitic  in 
type. 

We  have  noted  above  that  some  free  oil  was  found  to  be 
present  in  these  black  shales.  It  is  interesting  to  speculate 
as  to  whether  or  not  in  this  material,  potash  feldspar  has 
changed  over  into  shale  in  the  ordinary  way,  but  that  the 
free  oil  present  has  prevented  the  removal  of  the  more  soluble 
materials  by  an  excess  of  water. 

EXTRACTION  AND  CONCENTRATION  OF  THE  POTASH 

The  peculiar  character  of  these  shales,  which  seem  different 
from  any  potash  material  which  the  authors  have  found  de- 
scribed in  the  literature,  would  seem  to  warrant  a  search 
for  some  direct  method  for  the  extraction  of  the  potash.  The 
facts  already  presented  coupled  with  the  results  of  other  work 
that  we  have  done  preclude  the  possibility  of  finding  a  suc- 
cessful method.  Only  two-thirds  of  the  total  potash  content 
of  the  rock  can  be  extracted  with  acids  under  any  conditions. 
The  fine  grain  and  uniform  distribution  of  the  potash-carry- 
ing constituent  make  it  impossible  to  bring  about  any  mechan- 
ical separation. 

CONCLUSIONS 

1 — In  at  least  two  localities  in  Illinois,  shales  occur  which 
contain  5  per  cent  or  more  of  potash. 

2 — Shale  outcropping  in  several  places  near  Jonesboro, 
in  Union  County,  which  contains  5  per  cent  of  potash  would 
be  suitable,  so  far  as  can  be  determined  from  its  chemical 
composition  and  physical  character,  for  use  in  the  manu- 
facture of  portland  cement. 

3 — By  using  this  material  in  the  manufacture  of  cement 
and  by  applying  the  known  methods  of  potash  recovery,  a 
yield  of  5.3  Ibs.  of  potash  per  barrel  of  cement  could  be  ob- 
tained. 

4 — The  constitution  of  the  southern  Illinois  shale  is  com- 
plex. The  shale  contains  free  oil,  bituminous  matter,  pyrite, 
undecomposed  potassium-bearing  rock,  feldspathic  in  charac- 
ter, and  potassium-bearing  material  of  the  nature  of  glau- 
eonite  or  greensand. 

5 — Shale  from  Dixon,  Lee  County,  contains  5.8  per  cent  of 
potash,  which  is  held  for  the  most  part  in  a  more  stable  con- 
dition than  that  in  the  southern  Illinois  shale. 

6 — Extraction  of  the  potassium  from  shale  of  either  the 
southern  Illinois  or  the  Dixon  type  by  means  of  solid  or 
liquid  reagents  would  seem  to  be  impracticable,  because  of 
the  cost  of  leaching  and  recovering  potash  from  material 
where  it  is  present  in  such  small  amounts. 

7 — The  plant  availability  of  the  potash  in  the  southern 
Illinois  shale  is  probably  characteristic  of  all  the  material 
of  this  type  outcropping  in  that  locality. 

(6) 


8 — That  part  of  the  potassium  in  the  southern  Illinois  shale 
which  is  soluble  in  sulfuric  acid  is  shown  to  be  in  a  combi- 
nation of  the  glauconite  type. 

9 — In  southern  Illinois  shale  having  a  potash  content  of 
5.0  per  cent  in  the  raw  condition  or  5.6  per  cent  when  ignited, 
62  per  cent  of  the  total  potash  is  glauconitie  in  character  and 
is  available  as  plant  food. 


(7) 


VITA 

The  writer  of  this  thesis  was  born  on  a  farm  near  Water- 
loo, Wisconsin,  December  19,  1892.  Following  his  primary 
school  training  in  a  country  school,  he  entered  high  school 
at  Columbus,  Wisconsin,  and  graduated  after  a  four  years' 
course  in  1911.  The  year  following  graduation  from  high 
school  and  most  of  the  vacation  periods  since  were  spent  on 
a  farm.  He  entered  Lawrence  College,  Appleton,  Wisconsin, 
in  the  fall  of  1912,  and  after  four  years  at  that  institution, 
was  graduated  with  the  degree  of  Bachelor  of  Arts.  In  the 
fall  of  1916,  he  took  up  graduate  work  in  the  Department  of 
Chemistry  at  the  University  of  Illinois,  and  has  continued  in 
that  work  until  the  present  time.  He  received  the  degree  of 
Master  of  Arts  in  1918. 

While  in  attendance  at  the  University  of  Illinois,  he  has 
held  the  positions  of  Graduate  Assistant  (1916-1917),  Assist- 
ant (1917-1918),  Fellow  (1918-1919)  and  Assistant  (1919- 
1920).  He  enlisted  in  the  Engineer  Enlisted  Reserve  Corps  in 
February,  1918,  and  received  an  honorable  discharge  from 
that  organization  in  1919. 


Return  to  desk  from  which  borrowed. 
*"*  M  DUE  «  the  last  date  stamped  below. 


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